الفهرس 
- INTRODUCTION AND LITERATURE REVIEWOnly 14 pages are availabe for public view
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Abstract
Reducing the vibrations of structures using piezoelectric materials has long been a subject of study in many engineering fields; aeronautical, space, acoustic, sports engineering and so on. As a consequence, interest in the use of piezoelectric materials as actuators and sensors for controlling vibrations in flexible structures has also increased. Piezoelectric materials provide inexpensive, reliable, and nonintrusive means of actuating and sensing vibrations in flexible structures.
The goal of this work is to achieve maximum possible damping of structural vibration while minimizing the active control effort used. A new variable hybrid damping using the fuzzy logic is proposed for the switching actuation between two types of hybrid damping systems. A hybrid piezoelectric damping control system is a system which utilizes both active and passive control approaches in the damping operation of a vibrated structures .The availability of the proposed fuzzy hybrid piezoelectric damping system will be analytically demonstrated by simulating the response of a simple cantilever beam model with surface bonded piezo-elements.
The thesis consists of three main parts. The first part of the thesis develops a mathematical model of the physical resonant system-piezoelectric laminated cantilever beam. It is essential to have a good understanding of the physical system so that the associated problems with the hybrid active-passive damping can be addressed.
The second part introduces the two types of hybrid piezoelectric damping; one is a series (Integrated) type, where the piezoelectric actuators are actively driven by external voltage source with the passive tuned RL circuit in series. The other type is a separated type in collocated condition, where the external voltage source and the passive tuned RL shunting circuit are separated from each other, and both piezoelectric actuators to be used to the active and passive damping are collocated on the host structure.
The third part proposes a new type of piezoelectric damping. The new proposed system involves the use of the two hybrid damping systems. One of the two hybrid types is operated alone in a zone of structural vibrations where it is superior to the other. A fuzzy combination of the two types is made in a range between the two solo operating zones of each type. The Fuzzy switching rules between the two types is determined according to the vibration conditions of the host structure.
It will be demonstrated that the fuzzy switching type of the absorber is more efficient than a simple (linear) combination of the integrated/separated types.